Directional antenna system



June 18, 1940.

K. POSTHUMUS DIREQTIONAL ANTENNA SYSTEM Filed Deo. 20, I1938 KLA l 5 BY INVENTOR ATTORNEY Patented June 18, 1940 .r

UNITED STATES PATENT OFFICE DIRECTIONAL ANTENNA SYSTEM ration of Delaware Application December 20, 1938, Serial No. 246,769 In the Netherlands January 14, 1938 6 Claims.

This invention relates to a directional antenna system which has the property of concentrating the energy to beams extending in two directions perpendicular to each other.

According to the invention the system consists of a certain number of parallel radiating bodies each of which has an electric length 0f a half wave length, the two ends of at least a part of these radiating bodies being connected l0 to a non-radiating feed-system in such a manner that all of these radiating bodies are excited in the same phase.

The feed-system preferably consists of a double lead each of the conductors including loops which lie opposite each other at a distance of a half wave length and have an electric length of one or more half wave lengths.

'Ihe invention will be more clearly understood by reference to the accompanying drawing in which Figure 1 shows an embodiment of my invention and Figures 2 and 3 show modications thereof.

The antenna system shown in Figure 1 comprises a certain number of radiating bodies I,

2, 3 and 4 whose electric length corresponds to a half wave length and which are connected at both ends to a feed system consisting of the double conductor 5 and the loops 6, 1, 8 and 9 which are closed or not at the ends. In the form of construction illustrated the electric length of each loop amounts to two wave lengths and the spatial distance between the radiating bodies I and 2, 2 and 3, 3 and I amounts to a half wave length in each distance. The radiating bodies are connected to the loops in such a manner that all of them are excited in the same phase. To this end the radiating body I is, for instance, connected to the part 6 of the loop 6, whereas the radiating body 2 is connected to the part 6 of the loop 6. The other ends of the radiating bodies I and 2 are connected to corresponding points of the loop 1. Similarly the radiating bodies 3 and 4 are connected to the loops 8 and 9 as appears from the drawing. By lengthening the double conductor 5 and providing further loops extending parallel with the loops 'I, 8 and at mutual distances of a half wave length and which are connected through corresponding radiating bodies to the loops 1, 8 and may, if desired,

be interconnected, stronger concentration to a beam can be achieved in a vertical direction.

Furthermore, improved concentration to a beam in a vertical direction can be obtained by providing complementary radiating bodies I0 opposite the feedpoints at which the radiating bod- (Cl. Z50-11.5)

ies I, 2, 3 and 4 are connected to the loops 6, l, 8 and 9.

One advantage of this antenna system with series supply of the separate radiating bodies is that the points at which the loops are con- 5, nected to the double conductor 5 are potential nodes, so that these points may be supported by small insulators whereby the construction of the antenna system is rendered materially lighter and cheaper. 10

Figure 2 shows an improved embodiment of the invention which is endowed of the advantage that the whole antenna system extends in one plane so that the suspension is greatly simplified. This advantage is secured by providing in each 15 instance a crossing between two succeeding feedpoints of the system, since this measure permits the two parts of each loop to extend in the same plane as the radiating bodies.

In the form of construction shown in Figure 2 20 each conductor offthe double lead 5 comprises three loops 6, 1, I5and 8, 9, I3, respectively, the

loops 'I and I5 being connected through the intermediary of radiating bodies Il, I2 and the loops 8 and I6 being connected through radiat- 25 ing bodies I3, I4. Furthermore the form of construction represented in Figure 2 corresponds to that represented in Figure 1 but with the difference that crossings are in each instance provided in the loops between two succeeding feedpoints. These crossings are provided in such manner that upon connecting the radiating bodies to correspondingly arranged parts of each of the loops all radiating bodies are excited in the same phase. The whole system may be suspended 35 from the complementary radiating bodies l0 and the ends of the loops may be supported by two vertical antenna posts.

Figure 3 shows a simplified construction of the antenna system according to the invention where- 40 in the electric length of each loop amounts to a half wave length. The system comprises two groups of three radiating bodies which extend in line with each other and of which only the middle radiating body is fed at both ends. On ac- 45 count of the small width of the system it is not necessary to support the ends of the loops, so that the loop portions extending beyond the radiating bodies permit of being bent towards each other, if required, in view of the available space. 50

The antenna system according to the invention may be provided, if desired, with reflectors, whose construction corresponds to that of the antenna system, and may be located at a suitable distance behind the antenna. 55

I claim:

l. A directional antenna system comprising a plurality of half wave radiating members grouped in an end to end relationship in a plurality of vertical lines and means for energizing said radiators comprising a transmission line connected to a plurality of feed loops, said loops lying between the ends oi said radiators and connected thereto, said loops being crossed between adjacent lines whereby said radiators are energized in an iii-phase relationship.

2. A directional antenna oyster comprising plurality of half wave radiating l nbers grouped in an end to end relationship in a plurality of vertical lines spaced a ft a disiance equal to a half wavelength and means f energizing said radiators comprising a trannilssion line connected to a plurality of series connected iced loops, said feed loops lying between the ends of said radiators and connected thereto, said loops being crossed between adjacent lines whereby said radiators are energized in an in-phase relationship.

3. A directional antenna system comprising a plurality of heli wave radiati.. members grouped in an ond to end relationship in o plurality of parallel lines in a single vertical plane spaced apart a distance equal to a hall the length of he operating wave and means for energizing said radiators comprising a transmission line connected to a plurality of series connected feed loos, loops lyir g between the ends of said radiators and connected thereto, said loops eine; crossed betw -cn adjacent lines whereby said radiators are one giized in in--phase relationship.

4. A directional antenna system comprising a plurality of half ware radiating members grouped in an end to end relationship in a plurality of vertical lines and means for energizing said radiators comprising a transmission line connected to a plurality of feed loops, said loops lying between the ends of said radiators and conncced thereto, the distance between adjacent connoctions being equal to a nali \'.fa'\.'e1o. said loups being crossed between adjacent unos whereby said radiale s are energized in an iii-phase i l tionship.

5. A directional antenna system comprising a plurality oi half wave radiating member. grouped in an end to end relationship in a plr-.rality of vertical .lines spaced apart a distance equal to a half wavelength and means for energizing said radiators comprising a transmission line connected to a plurality of series connected leed loops, said feed loops lying between the ends of said radiators and connected thereto, the distance between adjacent connections being equal to a hall wavelength, said loops being crossed between adjacent lines whereby said radiators are energized in an iii-phase relationship.

G. A directional antenna system comprising a plurality of half wave radiating members grouped in an ond to end relationship in a plurality of parallel lines in a single vertical plane spaced apart a distance equal to a half the length of the operating wave and means for energizing said radiators comprising a transmission line connected to a plurality of series connected feed loops, said loops lying between the ends of said radiators and connected thereto, the distance between adjacent connections being equal to a half wavelength, said loops being crossed between adjacent lines whereby said radiators are energized in an in-phase relationship.

KLAAS POSTHUMUS. 

